The present invention relates to a guide tube to be inserted into a body cavity so as to smoothly guide the distal end portion of the flexible tube of an endoscope into the body cavity.
A guide tube of this type is disclosed in Japanese Utility Model Disclosure No. 57-42801. The tube comprises a flexible hollow cylinder to be inserted into a body cavity for inserting the distal end portion of the flexible tube of an endoscope the into a body cavity. The guide tube is used for two purposes. First, it is used to insert the distal end portion of an endoscope into a body cavity, thereby smoothly and repeatedly to reduce the patients suffering from the repeated insertions of the distal end portion into the body cavity. Secondly, it is used to suppress bending of the distal end portion due to reaction with the inner wall of the body cavity.
The guide tube cannot prevent, however, that part of the distal end portion which protrudes from the guide tube into the body cavity from being moved by peristaltic movement of the inner wall of the body cavity. This results in the following problem. When an endoscope is used to treat an affected tubercle within a body cavity, such as a polyp or a varix, an instrument such as a minute forceps is inserted into the body cavity via a channel provided in t he distal end portion of the endoscope. The instrument is guided to the tubercle. Then, the unit for operating the instrument, located at the proximal end of the flexible tube, is operated, thereby operating the instrument. That part of the distal end portion which extends from the guide tube is very likely to move due to the peristalitic movement of the inner wall of the body cavity. The affected tubercle also moves due to this peristaltic movement. Therefore, a great skill is required to operate the instrument-operating unit in order to move the instrument to the tubercle an drive it properly. As a result, nobody but a doctor who is skilled and much experienced in operating endoscopes can treat a affected tubercle within body cavity.